Mass transfer in pressure-driven membrane separation processes, Part II

Merdaw, A.A.; Sharif, Adel O.; Derwish, G.A.W.

doi:10.1016/j.cej.2010.12.072

Cited by 15 publications

(6 citation statements)

References 27 publications

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“…The Δ H hyd values of glucose and sucrose are −375 and −600 kJ mol −1 , respectively. 17 Now, in our case, divalent metal ions have a 3–5-fold higher Δ H hyd than carbohydrates, but still we observed a +ve chemotactic drift. Divalent metal ions have the coordinating ability with the core amino acid residue of the enzyme molecules which is also reflected in their ability to decrease the native zeta potential of the enzyme.…”

mentioning

confidence: 41%

Trade-off between carbohydrates and metal ions regulates the chemotactic directionality of alkaline phosphatase

2022

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mentioning

confidence: 41%

Trade-off between carbohydrates and metal ions regulates the chemotactic directionality of alkaline phosphatase

2022

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“…Therefore, the effect of temperature on N can be explained by considering that the extent of hydrophobic domains increases with increasing temperature. This is supported by the fact that the hydration of anionic groups is an exothermic process and associated with a negative entropy change. Consequently, increasing the temperature of the NPs dispersion would considerably disorganize the solvent water molecules around the surface charges, resulting in an increased probability of the dye reaching the NPs surface and being adsorbed.…”

Section: Resultsmentioning

confidence: 91%

Unraveling the Adsorption Mechanism of Rhodamine B onto Conjugated Polymeric Nanoparticles Using Isothermal Calorimetry and Monte Carlo Simulations

Ponzio,

Odella,

Prost

et al. 2024

J. Phys. Chem. C

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We present herein a comprehensive study on the thermodynamics of rhodamine B (RhB) adsorption onto poly(9,9dioctylfluorene-alt-benzothiadiazole) (F8BT) nanoparticles (NPs) dispersed in water using the isothermal calorimetric titration (ITC) technique. ITC experiments were carried out over a wide temperature range (5−65 °C), and the resulting thermograms were subjected to a detailed thermodynamic analysis using different adsorption models. For this purpose, we developed a versatile computational code based on the Monte Carlo method. We found that the thermograms obtained at the different temperatures cannot be interpreted using the Langmuir, bi-Langmuir, or Brunauer, Emmet, Teller (BET) models. However, excellent thermogram fits were attained by applying the Langmuir model coupled with the formation of a RhB dimer on the surface of F8BT NPs. Using this model, the best fit to the experimental data at 25 °C yielded the following parameters for direct RhB adsorption on the F8BT NPs surface: equilibrium constant (K l ) of ∼2 × 10 7 M −1 , enthalpy change (ΔH l ) of ∼1 kJ mol −1 , and entropy change (ΔS l ) of ∼140 J K −1 mol −1 . These results indicate that dye adsorption is predominantly an entropy-controlled process. The fit also provided parameters associated with the formation of a second dye adsorption layer, i.e., the formation of the RhB dimer on the F8BT NPs surface, revealing values of ∼1.7 × 10 5 M −1 , ca. −20 kJ mol −1 , and ∼30 J K −1 mol −1 for K m , ΔH m , and ΔS m , respectively. The latter two parameters are similar to those previously reported for RhB dimer formation in water (ΔH d = −12 kJ mol −1 and ΔS d = 22 J K −1 mol −1 ) supporting the chosen Langmuir-dimer model. The analysis of the thermograms also suggests that the NPs surface available for RhB adsorption is small, as compared to the total surface, and that it decreases with decreasing temperature. The latter observation is intriguing, especially since the F8BT NPs hydrodynamic diameter shows only a small decrease with decreasing temperature. To explain these results, we propose that the surface of the NPs harbors highly hydrated polar groups that reduce the accessibility of the dye for adsorption.

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“…A larger mean pore diameter may allow a higher transfer of solute molecules; however, this is limited by the solute diffusivity, which decreases by increasing the solute concentration. The dissociated solute ions, although smaller in size in comparison with the membrane mean pore diameter, are attached to larger-size hydration spheres hindering the mobility of the ions within the solution and inside the membrane material (Merdaw et al, 2011).…”

Section: Resultsmentioning

confidence: 99%

Effect of membrane mean pore diameter on water and solute flux in forward osmosis processes

al.¹

2022

Int. j. adv. appl. sci.

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Several forward osmosis (FO) experiments were carried out using aqueous solutions of sodium chloride (NaCl) in different concentrations, as draw solution (DS), and freshwater, as feed water (FW). The experiments were conducted at a constant temperature of ~20°C and using a symmetric cellulosic membrane in two grades different in their values of the molecular weight cut-off (MWCO), which is related to the mean pore diameter. This study investigates the effect of the membrane mean pore diameter on water flux and DS solute diffusional flux across the membrane. The value of water flux indicates the performance of the FO process, while solute flux is an important factor that determines its practicality. A proportionality factor is used to specify the relationship between water flux and solute flux for each membrane type and operational conditions. The results of this study show that water flux and solute flux increase as the solute concentration difference across the membrane increases. It is also found that, in the range of the tested membranes, membranes with larger mean pore diameters have lower water flux and higher solute flux.

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Mass transfer in pressure-driven membrane separation processes, Part II

Cited by 15 publications

References 27 publications

Trade-off between carbohydrates and metal ions regulates the chemotactic directionality of alkaline phosphatase

Trade-off between carbohydrates and metal ions regulates the chemotactic directionality of alkaline phosphatase

Unraveling the Adsorption Mechanism of Rhodamine B onto Conjugated Polymeric Nanoparticles Using Isothermal Calorimetry and Monte Carlo Simulations

Effect of membrane mean pore diameter on water and solute flux in forward osmosis processes

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